This invention relates in general to electrical outlet or junction boxes and deals more particularly with improvements in non-metallic outlet box assemblies.
In new building construction electrical outlet boxes are customarily installed before being wired and before wall material is applied. Such outlet boxes are usually nailed or otherwise fastened in fixed position to wall studs or the like, with proper allowance for the thickness of wall material to be later installed. The positioning of an outlet box is somewhat critical, since it generally determines the position of switches, receptacles or other electrical fixtures relative to the finished wall surface. Most outlet boxes heretofore available are not adapted for adjustment after installation. Any error in positioning such an outlet box must generally be compensated for by adjusting the positions of the electrical fixtures supported by the box. The mounting brackets on such fixtures are often provided with ears or the like for engaging marginal portions of the wall material which surrounds the wall outlet box opening. The ears cooperate with the marginal portions of the wall material to hold the fixture in proper position relative to the finish surface of the wall. However, such an arrangement is often not entirely satisfactory. When dry wall material is used, for example, the marginal portion of the material surrounding the outlet opening may lack the integrity to properly support the fixture.
Electrical codes generally require that the spacing between the outer surface of a wall and the frontal edges of an outlet box mounted within the wall must not exceed a specified dimension. If panelling is applied to the wall without repositioning the outlet box, the resulting structure may be in violation of the applicable code.
Since outlet boxes are usually secured in position before associated wiring is installed, it is often necessary for an electrician making the installation to work in close quarters or in awkward or uncomfortable positions to wire the outlet boxes, which may appreciably increase the time required to complete wiring installation.
When two or more outlet boxes are installed in side-by-side or stacked relationship to each other it is often necessary to remove a side wall from each of the boxes and connect the boxes to each other to form a larger box having a single chamber for containing all of the wiring to be terminated at the box location. However, this box arrangement is unacceptable for some purposes, as for example, where an electrical service cable and telephone, CATV and/or low voltage control conductors, which require physical separation from the electrical service cable, are terminated at a common location.
Electrical codes also generally require that electrical service cables be secured to associated outlet boxes to resist separation therefrom. For this purpose, most outlet boxes employ some form of clamping member secured by a threaded fastener or the like. The time required to secure the cables to each outlet box represent a significant portion of the overall time required to complete wiring installation.
When it becomes necessary to add to a service a single outlet box or a plurality of boxes arranged in stacked relationship after wall material is in place, problems are often encountered in fastening each box in position and in adjusting each box, as necessary, without damaging surrounding wall material.
The present invention is concerned with the aforedescribed problems. Specifically, it is the general aim of the present invention to provide improved non-metallic stackable electrical outlet box assemblies for rapid, accurate installation and which may, if necessary, be adjustably positioned after installation and relative to an associated wall.